Make sure its definatly what you want to do. Budget for a decent turbo as an old s12 t2 will be naff.Also think about a decent clutch at least an exedy s13 unit. Also you should fit a walbro fuel pump aswell and some sort of intercooler.
Bare that in mind as in a weekend and for quarter of the £ you could get a healthy s12 engine setup done
Det engines are great fun though
Are you definatly getting martins s12 then?